Carbon scraper



- r I j 1,620,822 I Marc 1 D. LAWSON v CARBON SCRAPER Filed June 21,. 1 926 G110. .17. LA 14/190 Patented Mauls, 1927.

,Ga aes i! masses, {FEQRTJDDDQEQIQWA= (CARBON Qs BE pp i atiom l ai s i The. objectfof this inventionfis to provide an improved" tool for scraping and'removing accumulations such asicarbon trom= a-lateral annular groove,--such-asthe'ring groove of a piston. V

, A further obiect is to provide an improved tool of the character described which has a plurality of improved and removable and replaceable cutting bits of any convenient size. a

A further object is to provide a tool of the character described which is adapted for use on pistons of varying diameter.

A further object is to provide such a tool comprising a spring band carrying the cutting bits and with integral handles adapted for compressing and manipulating the tool, said handles and adjacent portions of the band being concavo-convex in cross-section.

With these and other objects in view, my invention consists in the construction, arrangement and combination of elements hereinafter set forth, pointed out in the claims and illustrated by the accompanying drawing, in which- Figure l is a perspective view of the improved tool. V

Figure 2 is a plan view, partly in section, showing the tool in position for practical use relative to a piston.

Figure 3 is a section on the line 33 of Figure 2.

Figure 4c is an enlarged cross-section through one of the handles, on the line H of Figure 2. V The tool as shown is composed of a onepiece' band 10- formed ofspring steel and open at one point, from which project integral handles 11 and 11. The handles 11 vand 11 are conca-vo-convex in cross-section, With the concave sides directed inwardly and toward each other so that the convex surfaces form a convenient grip by which the handles may be brought toward each other in the handof a user to compress the band and manipulate the tool. The concavoconvex formation extends a considerable distance in each direction around the band 10, which is plain and curved on the'arc of a circle or cylinder in its central portion. The band is adapted to engage over and around a cylindrical object such as a piston 12 and is formed with cutting bits 13, in this instance four in number, spaced apart and directed inwardly on radial lines. The cutting bits 13 are adaptedto engage in an anieas. series-uh; 117,380.

nular -'groove such as l l' forr'n'ed in the outer surface-of the-pi ton for the re'eeption of the ordinary piston" wings, inwhich grooves there is a tendency tor -carbon toaccumulate projectingthrough a hole in the band 10 and secured in any suitable manner, as by riveting or by a nut 16 threaded on the stem outside of said band. I r

In practical use the band 10 is caused to embrace a pistonsuch as 12 in the manner shown, with the bits 13 entering the groove 14; The handles 11 and 11 are, then come pressed within the hand of the operator and the scraping operation is consummated by a rotary oscillation imparted to the band, causing the sharp'edges of the bits to bite, out and scrape the hardened accumulations and remove the same quickly and easily without injury to the pistonj' It is apparent that because ot' its spring construction, the tool does a not need to. be made exactly the diameteroi' the piston, and consequently one tool is adapted for use on a variety of pistons of different diameter. The concavo-convex construction adds strength to the handles and band and inakes'the handles of more con.-

. venient shape for grasping in the hand. The

two attenuated cutting or scraping edges of each bit make for efficiency in the scraping I operation, compensate for the curvature of the piston; The transverse curvature of the band preferably extends through an arc of at least ninety degrees from each of the handles 11 and 11 so that only the midportion thereof is plane transversely and capable of bending when the. handlesare compressed. This construction adds materially to the strength of the tool and prevents undesirable bending near the points of juncture of the handles when force is applied thereto in operating the tool. This curvature ofthe band extends well past the end bits, or those nearest the handles, and approximately to the more-remote bits near the center of the band, and gradually tapers out 60 in use. My tool is'for the purpose of scrap into or merges with the plane central portion of the band.

I claim as my invention-- 1. A spring band of circular form and open at one point, integral handles at the ends of said band, cutting bits carried by said band and projecting inwardly thereof, said handles andthe end portions of said band being curved transversely and the midportion of the band being plane transversely to permit bending and compression of th band by pressure on said handles. 7 a r 2. A carbon scraper, comprising a band of spring metal open at one point and provided with integral handles at its ends 15 adapted to be grasped in the hand of a user, and cutting bits on and projecting inwardly of said band, the handles being concavoconvex in cross-section and such curvature extending from each of said handles a considerable distance along the band and through an arc of at least ninety degrees from each end thereof.

EORGE D. LAWSON. 

